Automatic speed-increasing device.



No. 819,707. I PATENTED MAY 8, 1906 G. BABHR.

AUTOMATIC SPEED INOREASINGDEVIGE. APPLICATION FILED SEPT./1,1,1\904.

UNITED sTATEs PATENT oriuon GEORGE BAEHR, OF MOKEESPORT, PENNSYLVANIA, ASSIGNOR TO NATIONAL TUBE COMPANY, OF PITTSBURG, PENNSYLVANIA, A

CORPORATION OF NEW JERSEY. I

AUTOMATIC SPEED-INCREASING Device.

Patented May 8,1906.

Application filed September 17,1904. Serial No. 224,895.

To all whom it may concern Be it known that I, GEORGE BAEHR, a resident of McKeesport, in the county of Alletomatic Speed- Increasing gheny and State of Pennsylvania, have invented a new'and useful Im rovement in Au- I evices; and I do hereby declare the following to be a full,

' clear, and exact description thereof.

I the other will bebrought about automatically l by the load on said motor.

More specifically stated, the ob'ect of my "invention is to provide a system 0 this character which is adapted to drive a motor at a given low s eed when running idle orunder a friction or 'ght load and at a greater speed when running'under a heavier load, this're' 'sult being brought about by automatically 1 varying the resistance of the motor-field.

The invention also consists in providing a system of the character specified with manually-controlled means whereby the system vmavbe set to secure various rates of speed of l I the' motor when running at its higher speed 130' v mati'cally.

and in which when so set the change from the low to the higherlspeed will take place auto- In many industrial plants the machines are used'i'ntermittently, and thenature of the work is suchthat when the load is put on the .315

" rial to he {operated u on is presented to the f'machine, the latter s ould not exceed a cermachineg orpin other words, when the mate- ;f t'ain speed;- otherwise it is dificult to handlethe work or there is liability of damaging the same. -It, frequently occurs, however, thatgafter the work has been begun the machine-can be considerably speeded up without jdetrimentally affecting the work and sometimes with'tlie effect of improving it. If a a constant-s eed or a constant-current motor be empl o e for driving such machi nes, a will run at su 'stantially the same speed whemthe' machineis running idle as when the load is thrown thereon and as a result-the outputof the machine will'only be so much as it is-capable-of producing at thelow-speed at which the machine must be-run when the work is first'presented thereto. a

The object of my inv of the character described can when idle or tion is to provide an electric-motor system whereby machines under a friction load run at a comparatively slow s eed and without wasting the current,

but w ereby when the load is put on said-machine thefield of the motor will be automat icall weakened, so that the motor and the mac 'nedriven thereby will be speeded up.

My invention also consists in certain details of arrangement of the system, as will hereinafter appear.

In the accompanying drawings, Figure 1- shows diagrammatically one arrangement of my motor system, and Fig. 2 isa detail view showing a compound-wound motor in place of the series-wound motor of Fig. l. I

In the drawings the power mains are shown at 15 and 16.

' The translating device of the system is rep.-

resented by a motor whose armature is shown at 17 and field-magnet coils at 18. The motor-armature will be connected by suitable intermediate earing to the machine or machines to be riven. The motor illustrated in Fig. 1 is of the shunt-wound type.

In series with the field-magnets of the motor is a resistance device 19, which may be'ofany suitable formand which preferably will be adjustable manually, so that it can be" regulated at will. This resistance device is arranged to be cut into or out of circuit with the field-magnets of the motor automatically, ac

cording to the change of the motor from its friction or. idle load to its heavy load. The

arrangement is such that when the motor-is running idle or under its friction load the resistance device will be short-circuited, thus permitting the field to be at its maximum strength and decreasing the speed of the motor, Whereas when the load comes on the mof' I tor the short circuit will be broken, thus plac sultmaybeacco plished in variousways. In"

the drawings is sh wn an automatic magnetic .cireiiit making and breaking device for con'- .1 1n the resistance device in series w1th the trolling the short circuit or the resistance This circuit-controlling device consists of two terminals 21 and 22, located in the circuit on opposite sides of the resistance devicelQ, to-

gether with a conducting member 23, ar-- in series with the armature l"! of the motor, while the coil 29 is bridged across the l5 and 16. These coils are wound in opoosition and have the same number of windings or am ere-turns; but the coil 29 is oi finer wire, on therefore has a less currentcarrying capacity than the coil 28. An ad" ,lustsble resistance is laced in serieswitliv the coil 29. An adjusts le sprin 31 acts on anally short-circuit the resistance device 19.

the armature 26 to normally ho d the same away from the ole 27 of the magnet and to w really keep t e bridge-piece 28 in contact h the terminals 21 and 2-2, sees to nor the operation of the motor system de-- ed the resistance device 39 Will, be sued d that the coil 29 will ezractlyjbal nee under its friction load. As the two coils wound n opposition, no megnetic lines or force will be manifest at the pole 27, and as a consequence sprirg'al will. maintain the the art.

r circuit around the resistance device 19,. the field the motor will be at its 'rnum strength. This will give a relatively lowspeed to the snctcr, and as a conses'guence the e'connected to the motor will be such'a low speed that the work he sair'el presented thereto. As soon, however, as the work is fairly presented to the ins-chine an additional strain or load is thrown on the motor. This, as is well under stood, will slightly decrease the speed of the isnitor ai'mature, thus causing an increased flow of current through said armature. This increased current also passes through the coil the magnet, thus overbalancing the coil creating magnetic lines of force at the pole 2?. y This will attract the armature 26, h, through tne lever 24, will lift the -"oieoe 23, thus breaking the short cirund the resistance device 19 and pied ing said resistance in series with the field of the motor. As a result the motor field will bejweakened and said motor will speed up, as will be readily understood by those skilled in As soon as the work is withdrawn from the machine the load on the motor will suddenly and sharply decrease. This will cause the armature to momentarily speed up,

,thus increasing the counter electromotive This - device 19.

aqeoil 23 when the motor is running rid-leer;

stag/or 'force thereof and cutting down the current flowing through said armature. As a result the current flowing through the coil 28 will also be decreased to such an extent thatit w-illagain be balanced by the current flowing through the balancing-c0il 29. Hence the magnetic field at the pole 27 of the magnet will be destroyed or at least so for reduced that the spring 31 will be able to draw the armature 26 away from the magnet-pole and again establish the short circuit around the resistance The strength of the motor-field will therefore be a sin increased, and said motor will run at the lower speed. A compound-wound motor is also adapted for the purpose, this being shown in Fig. 2, the same motor, and the connection and regulation will he the same as with the arrangement shown in Fig. 1.. By the term a motor having a field-magnet in shunt'with the armsture in'the claims I intend to include both the shunt-motor shown in Fig. 1 and'also the compound motor shown in Fig. 2, as the latter has a field-magnet in shunt with its armature. I

By the system described the motor is driven at only two speedsa low speed when running under its friction load and a higherspeed when running under the heavier load. The higher speed can be varied by changing the variable-resistance device 19-. This 18 effected manually, so that the apparatus may be set to secure various high speeds, which is desirable for the reason that light work fre-- quently can advantageously be done at a greater speed than neev ier worlr. After bemg set to secure the desired higher speed the changes from the one speed to the other will be automatically brought about no matter at which higher s eed the resistance 19 may be set. This resu t is not dependent upon any variation in the difference of potential at the motor-terminals, but will be brought about even though the drop in potential should remain constant.

By means of the system described the speed of the motor will be increased and de creased entirely automatically. this being cl"- fected entirely by having the load thrown on or withdrawn from the motor. As a result the machines connected to the motor will be driven at such speed that the work can be safely resented thereto and will then be speeds up to very greatly increase the output. What I claim is 1: A self-regulating system for electric motors whose armatures are constantly under load, comprising a motor, a source of current ing-coil in shunt with the motor armature therefor, and automatic means controlled by the load on the motor and arranged to decrease the strength of the motor-field when the load on the motor-armature is increased, and to increase the strength of said field when the load on the motor-armature is decreased. v

' 2. A self-regulating system for electric motors whose armatures are constantly under load, comprising a motor, a.source of current therefor, and electrically actuated means controlled automatically by the load on the motor and arranged to decrease the strength of the motor-field when the load on the motor-armature is increased, and .to increase the strength of said field when the load on the motor-armature is decreased. I

3. A self-regulating system for electric 'motors whose armatures are constantly under load, comprising a motor, a source of current therefor, automatic means controlled by the load on the motor and arranged to increase he resistancet of the motor field-circuit when the load on the armature increases, and to decrease the resistance of said field-circuit when the load on the armature decreases, and manually-controlled means for varying the higher resistance of said field-circuit.

4. A self-regulating system for electric m0- tors whose armatures are constantly under load, comprising a motor, a source of current therefor, and'means actuated by the current flowing through the motor-armature and arranged to decrease the strength of the motorfield when an increased current flows through the motor-armature, and to increase the strength of the motor-field on a decrease of said current through the armature.

5: In an electric-motor system, the combination of a motorhaving a shunt-field, a source of current therefor, and means for regulating the strength of the motor-field, sald means comprising an electromagnet having a coil in series with the motor-armature and a balancing-coil in shunt with the motor armature and field.

6 In an electric-motor system, the combination of a motor, a source of current therefor, a resistance device, and means for cutting said resistance device into and out of series with the motor-field, said means comprising an electromagnet having a coil in series with the motor-armature and a balancand field. I

7 n an electric-motor system, the combination of-a motor having a field-magnet in shunt with its armature, a source of current therefor, a resistance device, and automatic means arranged to out said resistance device into and out of series with said shunt-field, said means comprising an electromagnet having a coil in series with the motorarmature and a balancing-coil in shunt with the armature and field.

8. In an electric-motor system, the combination of a motor having a field-magnet irr shunt with its armature, a source of current therefor, a manually-variable resistancedevice, and automatic means arranged to place said resistance device in series with said shunt-field magnet and to short-circuit the same, said means comprising an electromag-, net having a coil in series with the motor-armature and a balancing-coil in shunt with the motor armature and field.

9. In an electric-motor system, the combination of a motor having a field-magnet in shunt with its armature, a source of current therefor, and means for varying the strength of said shunt field-magnet, said means com- )rising an electrically-actuated device adusted to the friction load of the motor and having a coil in series with the motor-armature and a halancing-coil in shunt with the motor armature and field. i

10. In an electricmotor system, the comhination with. a motor having a field-magnet in shunt'with the armature, of a source of current therefor, a resistance device in series with the motor field-magnet, a short circuit for said resistance device which is normally maintained, a circuit-breaker in said short circuit, and means for operating said circuitbreakcr, said means comprising a coil in series with the motor-armature and a balancing-coil acting in opposition to. the firstnamed coil andin shunt with the motor armature and field.

1].. In an electric-motor system, the combination with a motor having a field magnet in shunt with the armature, of a source of current therefor, a resistance in series with the motor field-magnet, a short circuit therefor which is normally maintained, a circuitcontroller in said short circuit, and means for operating said circuit-controller comprising a magnet having two coils, one coil being in series with the motor-armature and the other coil being wound in oppositionthereto and being in shunt with the motor armature and field, and means for varying the strength'of said balancin -coil.

12. In an e ectric-motor system, the combination with a motor having a field-magnet in shunt with the armature, of a source of current therefor, a circuit controller arranged to vary the strength of said shunt field-magnet, and a magnet for operating said circuitcontrdiler,'*said' magnet comprising a coil in series with the motor-armature and a balancing-coil wound in opposition to said firstnam'ed coil and hein 1n shunt with the motor armature aid fie d.

13. In an electric-motor system, the com-Q bination with a motor having a field-magnet in shunt with the .aamatule, of a, source 01' current therefor, a, circuit-aontmfler arran 2 no vary aha strength a? said shunt field-11mg;- net, maguet far operating sircuit-cmltrailer, s. E magnefi @Mnpris'mg a C-Ufl in se ries with tba motor-mmature,f@ balancing coil acting in opposition tharetn and. in shunt with the meter almatxue and field, and

fitnesses Roma: 

